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1.
ONTHEBOUNDEDNESSANDTHESTABILITYRESULTSFORTHESOLUTIONOFCERTAINFOURTHORDERDIFFERENTIALEQUATIONSVIATHEINTRINSICMETHODCemilTUNC;A...  相似文献   

2.
THEASYMPTOTICEXPRESSIONOFTHESOLUTIONOFTHECAUCHY’SPROBLEMFORAHIGHERORDERLINEARORDINARYDIFFERENTIALEQUATIONWHENTHELIMITEQUATION...  相似文献   

3.
THERE-EXAMINATIONOFDETERMININGTHECOEFFICIENTOFTHEAMPLITUDEEVOLUTIONEQUATIONINTHENONLINEARTHEORYOFTHEHYDRODYNAMICSTABILITYLuoJ...  相似文献   

4.
APPROXIMATEINERTIALMANIFOLDSFORTHESYSTEMOFTHEJ-JEQUATIONSAPPROXIMATEINERTIALMANIFOLDSFORTHESYSTEMOFTHEJ-JEQUATIONS¥CaiRizeng(...  相似文献   

5.
EXISTENCETHEOREMSOFSOLUTIONSFORTWO-POINTBOUNDARYVALUEPROBLEMOFSECONDORDERORDINARYDIFFERENTIALEQUATIONSINBANACHSPACESZhangShis...  相似文献   

6.
THEBOUNDEDEXTERMINATIONANDSTABILITYOFMUTUALINTERFERENCESYSTEMOFFOUR-DIMENSIONALSPECIESHouGan-sheng(侯赣生)(Depl.ofPhysics,Jiangx...  相似文献   

7.
THEREMAINDER-EFFECTANALYSISOFFINITEDIFFERENCESCHEMESANDTHEAPPLICATIONSLiuRu-xun(刘儒勋)ZhouZhao-hui(周朝晖)(Dept.ofMath.Universityo...  相似文献   

8.
THEAPPLICATIONOFMULTI-SCALEPERTURBATIONMETHODTOTHESTABILITYANALYSISOFPLANECOUETTEFLOWZhouZhe-wei(周哲玮)(ShanghaiUniversily;Shag...  相似文献   

9.
UNCONDITIONALSTABLESOLUTIONSOFTHEEULEREQUATIONSFORTWO-ANDTHREE-DWINGSINARBITRARYMOTIONGaoZhenghong(高正红)(ReceivedJan.12,1995,C...  相似文献   

10.
INCREASINGPROPERTYOFSPECTRUMINTHEVIBRATIONSOFACYCLICCHAINOFMASSESDISTRIBUTEDACCORDINGTOTHEGTMSEQUENCEShangPengjian(商朋见)(Depar...  相似文献   

11.
基于单位分解的新型有限元方法研究   总被引:3,自引:1,他引:2  
刘欣  朱德懋 《计算力学学报》2000,17(4):422-427434
本文对基于单位分解概念的新型有限元方法具有一些新的特点进行了研究。这些新的特点包括自由度全部定义在单元顶点上,不同于传统的非协调和协调P型有限元方法自由度主要定义在单位区域内,因此很便于P型方法的实施;网格畸变度对解的不敏感性较传统有限元有了很大改进。此外,Dirichlet边界条件的处理与有限元是完全相同的,非常便利。论文分析了几个平面弹性问题:R.L.Tayor高阶分片试验和受拉弯剪切的平面悬臂梁,Cook悬臂T形板等,得到了满意的数值结果。  相似文献   

12.
We consider a homogeneous parallel shear flow of a multimode Maxwell fluid. This problem results in a set of ordinary differential equations for the stresses. In this system, we view the shear rate as a control and consider the problem of steering the system to a given state of stress. The objective is to steer the system from given initial stresses to a final state of stress, allowing the shear rate to vary in an arbitrary fashion. We show that this problem is related to a calculus of variations problem. For the case of two modes, we obtain a characterization of the set of achievable streses.  相似文献   

13.
It used to be considered that an axisymmetrical problem and a twist problem of an axisymmetrical body cannot be simulated by each other, because the number of unknown variables in an axisymmetrical problem is greater than that in a twist problem, and the governing equations are not the same. This paper proposes a degenerated analogy method, by which the twist problems of axisymmetrical bodies can be simulated by axisymmetrical problems with finite element programs.An ordinary structural analysis method can be used to analyze an axisymmetrical problem, but a twist problem of axisymmetrical bodies is treated as a 3-dimensional problem usually. According to the method proposed in this paper, the analysis of a twist problem can be simulated by the analysis of an axisymmetrical body with a structural analysis problem. The example of analysis computation is also given. Thecomputed result is in agreement with the theoretical result.In this paper, the constitutive relation of the degenerated analogy problem is given.The authors suggest that a twist problem of a body made of any materials is simulated by an axisymmetrical problem of a body made of orthotropic material. If you have to use some program for the axisymmetrical problem to be limited to isotropic materials the penalty coefficient method can be used to solve the problem.  相似文献   

14.
We consider thin-walled right-angle closed prismatic shells with rigid contour of the transverse cross-section. Such shells underlie the schemes used in the analysis of various thin-walled spatial structures. The use of nonlinear physical and geometric relations in the computations permits numerically obtaining the strength margin of the corresponding structures. In the present paper, we propose methods for obtaining a boundary value problem and analyzing such shells with nonlinear factors taken into account; the problem is presented as a system of linear differential equations with variable coefficients. We show that, within the approach proposed, this boundary value problem has a fixed structure independent of the special form of nonlinearity. The entire variety of problems of static analysis of right-angle prismatic shells with nonlinear factors taken into account can be reduced to solving this boundary value problem. Methods for taking a specific nonlinearity into account are treated as various methods for obtaining expressions for the variable coefficients in the matrices of the boundary value problem. We present methods for solving this boundary value problem numerically; these methods are independent of the specific form of the nonlinearity.  相似文献   

15.
In this paper the solutions of von Karman for elastic large deflection problem areclassified as the several solutions of Schr(?)dinger equation for quantum eigenvaluesproblem,and we present the transfrom for elastic large deflection problem from non-linearequation into linear equation.Thus,we create favourable conditions of the adoption ofconverse scattering methnd and B(?)cklund transformation.We also discuss the largedeflection problem of long and narrow plate.We can study the non-linear transition of elastic thin plate by furnished method fromthis paper.  相似文献   

16.
Optimal control theory is used to study the asymptotic behaviour of elasto-viscoplastic structures under cyclic loading. With this approach, the asymptotic state is found as the solution of a minimization problem. General properties of this method are established. A simple thermomechanical problem is studied to illustrate and validate this approach. An interest of the proposed method lies in its capacity to handle other nonlinearities than plasticity. To illustrate this point, the approach is extended to the coupled viscoplasticity/frictionless contact problem. Some numerical results are given for an elasto-viscoplastic half-plane under cyclic frictionless indentation.  相似文献   

17.
In this paper we deal with the Dirichlet problem for quasilinear elliptic equation with a small parameter at highest derivatives. In case the characteristics of the degenerated equation are curvilinear and the domain, where the problem is defined, is a bounded convex domain, we offer a method to construct the uniformly valid asymptotic solution of this problem, and prove that the solution of this problem really exists, and being uniquely determined as the small parameter is sufficiently small.  相似文献   

18.
In this paper, we prove that the OGY method to control unstable periodic orbits (UPOs) of continuous-time systems can be applied to a class of systems discontinuous with respect the state variable, by using a generalized derivative. Because the discontinuous problem may have not classical solutions, the initial value problem is transformed into a set-valued problem via Filippov regularization. The existence of the ingredients necessary to apply OGY method (UPO, Poincaré map and stable and unstable directions) is proved and the numerically implementation is explained. Another possible way analyzed in this paper is the continuous approximation of the underlying initial value problem, via Cellina??s theorem for differential inclusions. Thus, the problem is approximated by a continuous initial value problem, and the OGY method can be applied as usual.  相似文献   

19.
This work is the continuation of the discussions of [50] and [51]. In this paper: (A) The Love-Kirchhoff equation of small deflection problem for elastic thin shell with constant curvature are classified as the same several solutions of Schrodinger equation, and we show clearly that its form in axisymmetric problem;(B) For example for the small deflection problem, we extract me general solution of the vibration problem of thin spherical shell with equal thickness by the force in central surface and axisymmetric external field, that this is distinct from ref. [50] in variable. Today the variable is a space-place, and is not time;(C) The von Kármán-Vlasov equation of large deflection problem for shallow shell are classified as the solutions of AKNS equations and in it the one-dimensional problem is classified as the solution of simple Schrodinger equation for eigenvalues problem, and we transform the large deflection of shallow shell from nonlinear problem into soluble linear problem.  相似文献   

20.
We consider a simple but fully three-dimensional inverse problem to determine the shape of a local perturbation of a perfectly conducting plate from far-field measurements of time harmonic electromagnetic fields. For this purpose we reformulate the model problem as an exterior Maxwell problem for a symmetric domain, and prove an equivalence between the model problem and its reformulation. Then, linear sampling method is applied to solve the reformulated problem. We illustrate the feasibility of this method by some numerical examples.  相似文献   

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